Final answer:
To find the probability that Mason does not arrive at work by 9 am, we need to consider the scenarios where his bus is on time and his bus is late. Using the multiplication rule, the probability is found to be 1/8.
Step-by-step explanation:
To find the probability that Mason does not arrive at work by 9 am, we need to consider the scenarios where his bus is on time and his bus is late. Since the probability that his bus arrives on time is 1/2 and the probability he arrives at work by 9 am given that his bus is on time is 3/4, we can calculate the probability using the multiplication rule:
P(Mason does not arrive at work by 9 am) = [P(bus is on time)] * [P(he arrives at work by 9 am given that bus is on time)] + [P(bus is late)] * [P(he arrives at work by 9 am given that bus is late)]
P(Mason does not arrive at work by 9 am) = (1/2) * (1 - 3/4) + (1/2) * (1 - 3/4) = 1/8
Therefore, the probability that Mason does not arrive at work by 9 am is 1/8.